Concorde Fuel Management

[Zeuss_1238 0]

Hi,

Hopefully this is the right forum to post this (hopefully at least someone knows the fuel system of Concorde)

Last week, I began my journey into learning the extremely complex systems of Concorde. Up until now I have just been learning the basics but yesterday I began studying the intricate fuel management system and the engineering behind it. To strengthen my understanding, I read up on a few documents like the FSLabs Concorde X manual and watched a few videos such as the youtube video from UPS1000 titled "ConcordeX - Master the Fuel Panel".  Some of you might already be familiar with the video (it has around 30k views) but I will link it below with the timestamp I am referring to for context.

Now, in the FSLabs Concorde X manual (page 140) there is a helpful graphic "Tank Locations & Transfer Guide" where it simply states to transfer from 8 to 5 using the interconnect valve:

My confusion comes in when UPS1000 is balancing the fuel during cruise at around 39:52 in the video:

 I understand the concept of moving fuel from the right side of the plane to the left to balance the aircraft but in the video he transfers fuel from tank 8 to tank 5 by moving it in the order:

8 to 3, 3 to 11, then 11 to 5

My question is why doesn't he simply use the interconnect valve to transfer from 8 to 5 instead of doing this seemingly complicated sequence? In the documentation of Concorde X is even states that the interconnect valve is to be used to transfer fuel from 8 to 5 (page 147). Additionally, why does he transfer from 8 to 5 instead of tank 8 to 6 and 7 to tank 5? In my mind we should transfer from 8 to 6 and 7 to 5 due to size of the tanks.

How can I approach this differently? Does anyone have some insight on the Concorde fuel tank management system? Thanks for any help 🙂

edit: I should note I am not learning using FSLabs Concorde X, rather, the Colimata Concorde FXP for Xp11 and 12.Sadly,  it doesn't come near the complexity of Concorde X (still a beautiful product and I love it) so I decided to watch this youtube video to help anyway. I was also recommended by UPS1000 himself in the comments of his video to make a post here

Edited January 16, 2023 by Zeuss_1238

[Bob Scott 7,721]

Fuel management on the Concorde is at least as much about managing the CG as it is about left-to-right fuel balance.  The CL shifts as the jet transitions in/out of supersonic flight, so the CG has to be kept in a range relative to the CL during the different phases of flight.

@Ray Proudfoot is the guy to ask about exactly why he'd do it this way, but I'm pretty sure it was done that way to have the transfer also facilitate CG management.

[Ray Proudfoot 8,976]

Linus, the management of fuel on Concorde is quite complex and I’m only familiar with the procedures on the FS Labs 32-bit Concorde. I have no idea if the Colimata version allows transfer in the same way as the FSL one.

As Bob says it’s all about keeping the CG within the forward and aft limits. Tanks 9 and 10 were the first to be emptied as fuel was transferred rearwards to 11 until that tank contained 10.5T after which the remainder was moved to tanks 5 and 8.

No lateral transfer was normally required. Tanks 5,6,7 and 8 are all different capacities but each pair on the left and right contained around the same amount. It’s not possible to transfer directly from one side to the other. It has to go via tank 11. That makes it more complicated but that’s how it worked in the actual aircraft.

Tanks 5 and 8 would feed 1,2,3 and 4 and when empty 6 and 7 were used. Earlier in the flight 5A and 7A were emptied into 5 and 7.

Once the decel / descent started the CG would move forward from 59 and that’s where the 10.5T in 11 was pumped forward into 5 and 8 which in turn fed 1,2,3 and 4. A small amount was moved into tank 9 for landing.

On final approach fuel only remained in 1,2,3 and 4 plus a small amount in 9.

The YT video you linked to is an excellent guide. He goes into great detail but it is a complicated topic and requires much practice. I only started moving fuel myself after many years of leaving it to the VFE. But managing it is very rewarding.

The FS Labs 64-bit Concorde is due in the next few months if you want to try what looks like being the best available.

 

[Zeuss_1238 0]

38 minutes ago, Ray Proudfoot said:

Linus, the management of fuel on Concorde is quite complex and I’m only familiar with the procedures on the FS Labs 32-bit Concorde. I have no idea if the Colimata version allows transfer in the same way as the FSL one.

As Bob says it’s all about keeping the CG within the forward and aft limits. Tanks 9 and 10 were the first to be emptied as fuel was transferred rearwards to 11 until that tank contained 10.5T after which the remainder was moved to tanks 5 and 8.

No lateral transfer was normally required. Tanks 5,6,7 and 8 are all different capacities but each pair on the left and right contained around the same amount. It’s not possible to transfer directly from one side to the other. It has to go via tank 11. That makes it more complicated but that’s how it worked in the actual aircraft.

Tanks 5 and 8 would feed 1,2,3 and 4 and when empty 6 and 7 were used. Earlier in the flight 5A and 7A were emptied into 5 and 7.

Once the decel / descent started the CG would move forward from 59 and that’s where the 10.5T in 11 was pumped forward into 5 and 8 which in turn fed 1,2,3 and 4. A small amount was moved into tank 9 for landing.

On final approach fuel only remained in 1,2,3 and 4 plus a small amount in 9.

The YT video you linked to is an excellent guide. He goes into great detail but it is a complicated topic and requires much practice. I only started moving fuel myself after many years of leaving it to the VFE. But managing it is very rewarding.

The FS Labs 64-bit Concorde is due in the next few months if you want to try what looks like being the best available.

 

Thank for your response! It unfortunately does not translate at all into the Colimata as trimming of the fuel is done automatically and instantly by the VFE. There is an additional mod for the Colimata that allows for better fuel management but I have yet to try it. I am simply getting prepared for future Concorde releases and just wanting to learn more about the aircraft. Perhaps in the future I can put together my own fuel management system for the Colimata if the mod isn't adequate but for now I am just diving into the deep and complex systems of the plane 🙂

A few last things, if the transfer between 5 and 8 is not usual under normal circumstances and is much slower than transferring it through tank 11, why does the interconnect valve even exist at all? Just for emergency situations?

Also, in the video it seems that he has the pumps for 6 and 7 on during this balance but the tanks in 5 and 8 are not emptied yet after the balance? Do you just keep all pumps on? edit: OH, I see now! It all seemed to click just now after watching that section of the video again. He has tank 6 on because tank 5 was almost empty before the balance! Disregard the second question then

Edited January 16, 2023 by Zeuss_1238

[Ray Proudfoot 8,976]

23 minutes ago, Zeuss_1238 said:

Thank for your response! It unfortunately does not translate at all into the Colimata as trimming of the fuel is done automatically and instantly by the VFE. There is an additional mod for the Colimata that allows for better fuel management but I have yet to try it.

Instantly? Hmmm. Not ideal but the amount of programming to have all 13 tanks operational makes it understandable. Give it a try. As long as the CG bug remains between the forward and aft limits it should be okay.

I don’t really know why fuel could be cross fed. Probably to cater for non-standard situations. They thought of everything back then. 😁

One other point. On the LHR-JFK run the aircraft never reached FL600 with a healthy number of pax. The troposphere just isn’t cold enough that far north. If the Colimata is regularly reaching that altitude then the modelling is off.

It was reached nearer the tropics as with the Barbados run where the upper air is much colder. Jet engines love cold air. 😉

[Zeuss_1238 0]

16 minutes ago, Ray Proudfoot said:

Instantly? Hmmm. Not ideal but the amount of programming to have all 13 tanks operational makes it understandable. Give it a try. As long as the CG bug remains between the forward and aft limits it should be okay.

I don’t really know why fuel could be cross fed. Probably to cater for non-standard situations. They thought of everything back then. 😁

One other point. On the LHR-JFK run the aircraft never reached FL600 with a healthy number of pax. The troposphere just isn’t cold enough that far north. If the Colimata is regularly reaching that altitude then the modelling is off.

It was reached nearer the tropics as with the Barbados run where the upper air is much colder. Jet engines love cold air. 😉

Yes this is another unfortunate detail of the Colimata, reaching FL600 is very unlikely. So far with my flights I have reached FL600 easily and the aircraft wants to climb even further. In my opinion, they've had plenty of time to address this but I know it's complex. The tutorials I've used shed this off casually but it is still upsetting that some of the more important aspects of the aircraft are not modeled correctly.

And yes, fuel transfer is instant. I have yet to really test out the xp12 version but in the xp11 version many suggest you skip trimming for descent as the sudden shift in CG makes the autopilot lose control of the aircraft for a bit. Really not ideal so I hope they've fixed some of these aspects in the xp12 version.

While I love the Colimata version I simply cannot wait for an extremely high detailed model of the aircraft to be released again. I would love to take a look at some of the inner workings of the code because this kind of modelling and detail is unrivaled especially for an aircraft like this.

Edited January 16, 2023 by Zeuss_1238

[Ray Proudfoot 8,976]

Linus, have you queried this behaviour on the Colimata forum? Are there any plans to refine the FE panel so manual control of fuel movement is possible?

Ultimately it’s your choice which Concorde you feel is the best. I have no doubt which I consider it to be. Nothing stopping you from buying P3D and the forthcoming FSL version.

[MachTwo 386]

@Zeuss_1238,

I can't speak much for Concorde-X - even though I wrote it, it was so long ago and differs somewhat to our new version currently in development for P3D and MSFS.

Firstly, fuel was moved laterally pretty much on every flight. The engines all burnt off fuel at slightly different rates - and any lateral discrepancy between the elevons would incur a performance penalty. As the fuel burnt off in the super cruise the CG would move rearward, and so fuel was periodically moved forward out of the rear tank into the wing tanks to maintain a CG of 59%. This operation alone was normally enough to keep things in balance laterally, as the EO would move the fuel out of T11 and into the wing tanks preferentially. 

If additional lateral transfer was required, the correct procedure was to move the fuel out of the collector tanks, via the jettison valve into the trim manifold (two manifolds, one each side) and through Tank 11 into the opposite wing. The tank interconnection valves used a gravity feed system, so it was much slower. It was only used as a backup.

The CG was brought forward partially, shortly before the deceleration point to cool the wings, normally in conjunction with the procedure that was followed when coming out of aft trim.

[Zeuss_1238 0]

6 hours ago, Ray Proudfoot said:

Linus, have you queried this behaviour on the Colimata forum? Are there any plans to refine the FE panel so manual control of fuel movement is possible?

Ultimately it’s your choice which Concorde you feel is the best. I have no doubt which I consider it to be. Nothing stopping you from buying P3D and the forthcoming FSL version.

Luckily I already have P3D so it will be a quick switch over when something gets released 🙂

The Colimata team (maybe its one person I am not sure actually) is focused on other details about the aircraft right now I think. With the release of XP12 I am sure the focus is FPS performance and ironing out bugs. The V3 version released has significant improvements. For example Max Climb works now! I am not to sure if this was added earlier than V3 but I remember when learning the aircraft a few years ago we had to manage around climb to cruise using vert speed mode which was a bit sad. Honestly the only reason I keep on X-Plane is for Concorde and maybe the 767 (A340 too maybe) but on XP12 Colimata Concorde is my only add-on at the moment. I love it still but of course I still wait patiently for some competition and an add-on where I can finally apply this knowledge about these systems. I was disappointed to learn this information on this post and then load up Concorde to find many systems are not included and you yourself cannot even shift fuel around the aircraft--just turn on pumps and inlets and such.

This post from the Colimata forum details what I just said about it being added later. Granted, it's from a few years ago but it still hasn't been added...at least not to the extent we discussed.

https://forums.x-plane.org/index.php?/forums/topic/254267-question-about-the-fuel-system/

 

3 hours ago, MachTwo said:

@Zeuss_1238,

I can't speak much for Concorde-X - even though I wrote it, it was so long ago and differs somewhat to our new version currently in development for P3D and MSFS.

Firstly, fuel was moved laterally pretty much on every flight. The engines all burnt off fuel at slightly different rates - and any lateral discrepancy between the elevons would incur a performance penalty. As the fuel burnt off in the super cruise the CG would move rearward, and so fuel was periodically moved forward out of the rear tank into the wing tanks to maintain a CG of 59%. This operation alone was normally enough to keep things in balance laterally, as the EO would move the fuel out of T11 and into the wing tanks preferentially. 

If additional lateral transfer was required, the correct procedure was to move the fuel out of the collector tanks, via the jettison valve into the trim manifold (two manifolds, one each side) and through Tank 11 into the opposite wing. The tank interconnection valves used a gravity feed system, so it was much slower. It was only used as a backup.

The CG was brought forward partially, shortly before the deceleration point to cool the wings, normally in conjunction with the procedure that was followed when coming out of aft trim.

Very useful information thank you! I am glad there are still plenty of people who understand the systems of Concorde. While there is information online topics like this one are rather scarce; at least from what I looked at. Will the Concorde that is releasing for P3D and MSFS have an in depth fuel management system like that of Concorde-X? I am assuming the answer is yes but I am curious how it differs.

Thanks for the replies guys I am learning a lot!

[Ray Proudfoot 8,976]

3 minutes ago, Zeuss_1238 said:

I still wait patiently for some competition and an add-on where I can finally apply this knowledge about these systems. I was disappointed to learn this information on this post and then load up Concorde to find many systems are not included and you yourself cannot even shift fuel around the aircraft--just turn on pumps and inlets and such.

The competition is the FSL version. If the only reason you’re keeping XP is for a far from perfect Concorde cut your loses and wait for the FSL version. The Colimata version has been around for a few years and some things should be working by now.

3 minutes ago, Zeuss_1238 said:

Very useful information thank you! I am glad there are still plenty of people who understand the systems of Concorde.

Andrew is the main programmer for the FSL Concorde if you weren’t aware. 😉

[Zeuss_1238 0]

On 1/17/2023 at 12:22 PM, Ray Proudfoot said:

The competition is the FSL version. If the only reason you’re keeping XP is for a far from perfect Concorde cut your loses and wait for the FSL version. The Colimata version has been around for a few years and some things should be working by now.

Andrew is the main programmer for the FSL Concorde if you weren’t aware. 😉

Wow! Can't wait for the new Concorde! I'll be the first in line when it comes out. Well, maybe after you 😉

[Zeuss_1238 0]

Also, as it turns out Colimata does have manual fuel management but you have to switch it on which is why my fiddling with the switches was doing nothing! I feel the fuel flow rate is slightly too high though...maybe the dials just update quicker in comparison to the Concorde-X though

Edited January 19, 2023 by Zeuss_1238

[Ray Proudfoot 8,976]

8 hours ago, Zeuss_1238 said:

Also, as it turns out Colimata does have manual fuel management but you have to switch it on which is why my fiddling with the switches was doing nothing!

That would be the default setting. Same on the FSL version. Too much for the beginner to cope with so that’s why it’s left to the Virtual Flight Engineer.

[MarkW 1,493]

@Zeuss_1238 - Thanks for posting here, I knew you would get expert advice from Ray and Andrew.  Although I made the fuel video it has been a long time since I have flown Concorde having ditched P3D v3 many years ago.  As with many, looking forward to seeing her in MSFS at some point in the future.

[Ray Proudfoot 8,976]

Hi Mark, can't you be tempted to return to P3D purely for the best Concorde we'll ever get? Your skills in mastering the fuel management and producing such a quality video are widely acknowledged. They should do Oscars for this kind of work!

Given most flights were over open ocean you could get by with a default v5 or more likely v6, ActiveSky and Chaseplane.

I can't help but feel the release for MSFS will be some way off.